Hearing aid including a piezo assembly and an electromagnetic assembly

ABSTRACT

According to an aspect of the present disclosure, a hearing aid is disclosed. The hearing aid including a vibrator configured to apply a main vibration stimulation onto a skull of a recipient of the hearing aid. The vibrator may include a first assembly which comprises a magnet configured to provide a static magnetic flux and a coil configured to provide a dynamic magnetic flux based on a first current, and the coil may be wrapped around at least a part of the magnet. Furthermore, the vibrator includes a second assembly which includes a vibrator transfer unit and a suspension spring, and wherein the first assembly may be configured to move relative to the second assembly generating a first vibration based on the static and the dynamic magnetic flux, and the first vibration may be transferred to the vibrator transfer unit. Additionally, the vibrator includes a first piezo assembly configured to move based on a second current generating a second vibration, and wherein the first piezo assembly may be connected to the vibrator transfer unit, and when the first piezo assembly moves, a second vibration may be generated, and the second vibration may be transferred to the vibrator transfer unit. The main vibration which is transferred to a skull of the recipient via the vibrator transfer unit may include the first vibration and/or the second vibration.

FIELD OF THE DISCLOSURE

The present disclosure relates to a hearing aid including a vibrator.More precisely, the hearing aid includes a vibrator which combines piezoand electromagnetic generated vibrations for improving the hearingcapability of a recipient of the hearing aid.

BACKGROUND

Medical implants such as bone anchored hearing aid systems are appliedfor the rehabilitation of patients suffering from hearing losses forwhich traditional hearing aids are insufficient. A typical bone anchoredhearing aid system comprises an external hearing aid provided with avibrator connected to a skin-penetrating abutment through a coupling. Analternative bone anchored hearing aid system comprises an external partand an implant in which the vibrator is arranged. A common vibrator isan electromagnetic transducer which has a rather narrow resonance peak,where efficiency and sound output is highest. This resonance peak isnormally designed to be around 1000 Hz, and this results in limitedmaximal sound transfer at low frequencies below 600 Hz and very highfrequencies above 3000 Hz. The human brain needs to process vibrationand sound between 500 Hz and 8000 Hz to process speech in a good way. Avibrator for a hearing aid having a wider frequency range is thereforedesired. When using a vibrator having one vibrator source for generatingvibration, i.e. sound excitation, usually one resonance peak can beachieved through the design of the source, however, if multiple vibratorsources are used multiple resonance peaks can be generated, resulting ina wider frequency range with high output and high power efficiency. Dueto the size constraints of a hearing aid, it is rather difficult toarrange multiple vibrator sources within a vibrator which must fit intoa hearing aid having strict size constraints. Therefore, there is a needto provide a vibrator for a hearing aid having multiple vibrator sourceswith a minimal size increase of the hearing aid when comparing to avibrator including a single vibrator source.

Furthermore, another constraint to the hearing aid is the powerconsumption. Currently power is supplied analog to the vibrator, whichresults in a movement of the transducer and a force output. By havingmore vibrator sources in the vibrator demands more advanced energytransfer algorithms for lowering the power consumption of the hearingaid.

Therefore, there is also a need to improve the power consumption of thehearing aid when including multiple vibrator sources for increasing thefrequency range of the vibrations.

SUMMARY

An aspect of the present disclosure is to provide a hearing aid having avibrator with an improved frequency bandwidth around a resonancefrequency of the vibrator.

Another aspect of the present disclosure is to provide a hearing aidwith improved power consumption when including a vibrator with animproved frequency bandwidth.

An even further aspect of the present disclosure is to provide avibrator with the possibility of tuning the frequency bandwidth and/orthe resonance frequency.

According to an aspect of the present disclosure, a hearing aid isdisclosed. The hearing aid including a vibrator configured to apply amain vibration stimulation onto a skull of a recipient of the hearingaid. The vibrator may include a first assembly which comprises a magnetconfigured to provide a static magnetic flux and a coil configured toprovide a dynamic magnetic flux based on a first current, and the coilmay be wrapped around at least a part of the magnet. Furthermore, thevibrator includes a second assembly which includes a vibrator transferunit and a suspension spring, and wherein the first assembly may beconfigured to move relative to the second assembly generating a firstvibration based on the static and the dynamic magnetic flux, and thefirst vibration may be transferred to the vibrator transfer unit.Additionally, the vibrator includes a first piezo assembly configured tomove based on a second current generating a second vibration, andwherein the first piezo assembly may be connected to the vibratortransfer unit, and when the first piezo assembly moves, a secondvibration may be generated, and the second vibration may be transferredto the vibrator transfer unit. The main vibration which is transferredto a skull of the recipient via the vibrator transfer unit may includethe first vibration and/or the second vibration.

The vibrator transfer unit may be shaped as a rod configured to receivethe vibration (the first and/or the second vibration) and transfer themain vibration onto a skull either directly to the skull or via animplant screw fixated to the skull of the recipient. In another example,the vibrator transfer unit may be a plate with a protrusion wherein theplate is configured to receive the vibration and apply the mainvibration via the protrusion directly onto the skull or via an implantscrew fixated to the skull of the recipient. The implant screw in bothexamples may be replaced by a skin interface plate which is connected tothe vibrator transfer unit and which is in direct contact to the skin ofthe recipient. In yet another example the vibrator transfer unit may bea plate which transfer the main vibration to a housing which is indirected contact to the skull of the recipient or indirect contact viaskin and tissue of the recipient.

An advantage of the first assembly and the first piezo assembly areusing the same vibrator transfer unit is that the size increase of thehearing aid due to applying an additional vibrator is rather limited, ifany at all, as an additional vibrator transfer unit is not needed. Thefirst piezo assembly may be integrated into the vibrator transfer unitin order to avoid any size increase of the hearing aid by applying anadditional vibrator.

The housing may include the first assembly, the second assembly and thefirst piezo assembly. The housing may be implanted such that the housinghas direct contact to the skull. In another example, the housing may bearranged directly onto the skin of the recipient or onto an abutmentwhich is in contact with the skull of the recipient via an implantscrew. A transcutaneous hearing aid is when the housing is implanted,and a percutaneous hearing aid is when the housing is in contact withthe skull of the recipient via an implant screw.

The hearing aid may include a processing unit configured to control thefirst current and the second current based on an audio signal providedby at least one microphone of the hearing aid. The processing unit maybe arranged within the housing, i.e. a first housing, or in a secondhousing, wherein the second housing may be connected to the firsthousing either wirelessly or via a wired connection. The second housingmay be implanted or not implanted. The processing unit may be part of anexternal device, such as a computer or a portable device, such as asmartphone, a tablet or a smartwatch, wherein the external device isconfigured to communicate wirelessly to the first housing and/or thesecond housing.

The vibrator may comprise a second piezo assembly configured to movebased on a third current and generate a third vibration, and wherein thesecond piezo assembly transfer the third vibration to the vibratortransfer unit, and wherein the main vibration to the skull includes atleast the first vibration and/or the second vibration and/or the thirdvibration. The housing may also include the at least second piezoassembly. By applying at least the second piezo assembly results in aneven more broader frequency bandwidth of the

The first piezo assembly and/or the second assembly may include amultilayer piezoelectric element comprising two stacked piezoelectriclayers, and a flexible passive layer disposed between and mounted to thepiezoelectric layers, wherein the piezoelectric layers are configured todeform in response to application thereto of electrical signals, such asa current, generated based on the received sound signals. A masscomponent may be attached to the multilayer piezoelectric element so asto move in response to deformation of the piezoelectric element; and acoupling configured to attach the hearing aid to the recipient so as totransfer the main vibration, i.e. output forces, of the vibratortransfer unit to the recipient's skull.

The first piezo assembly and/or the second assembly may include amultilayer piezoelectric element comprising two stacked piezoelectriclayers separated by a substantially flexible passive layer, wherein thepiezoelectric layers have opposing directions of polarization such thatapplication of electric signals, such as current, generated based on areceived sound signals, to both of the layers causes deflection of thepiezoelectric element in a single direction; a mass component attachedto the multilayer piezoelectric element so as to move in response todeformation of the piezoelectric element; and a coupling configured toattach the hearing aid to the recipient so as to transfer the mainvibration, i.e. output forces, generated by the multilayer piezoelectricelement and the mass component to the recipient's skull.

The first piezo assembly may have at least a first end and a second endrelative to a center of the first piezo assembly, and wherein the firstpiezo assembly may have a first connection to the vibrator transfer unitarranged at the first end or between the first end and the center and asecond connection to the vibrator transfer unit arranged at the secondend or between the second end and the center.

The at least second piezo assembly may have at least a first end and asecond end relative to a center of the at least second piezo assembly,and wherein the at least second piezo assembly may have a firstconnection to the vibrator transfer unit arranged at the first end orbetween the first end and the center of the at least second piezoassembly and a second connection to the vibrator transfer unit arrangedat the second end or between the second end and the center of the atleast second piezo assembly.

The vibration generated by the first piezo assembly and/or the secondpiezo assembly may be transferred to the vibrator transfer unit via thefirst connection and the second connection, and the main vibration maythen be forwarded by the vibrator transfer unit to the skull of therecipient. The first connection and the second connection may be made ofa material which able to transfer vibration with a certain efficiencysuitable for a hearing aid 1. For example, the both connections may bemade of a plastic material or a metal material or a combination of thetwo materials. The connections may be welded or glued to either thepiezo assembly and/or the vibrator transfer unit. Alternatively, theconnections may be connectable to the piezo assembly and/or the vibratortransfer unit via a mechanical interface which makes it possible removethe piezo assembly from the vibrator transfer unit.

The first piezo assembly and/or the at least second piezo assembly maybe connected to an outer surface of the vibrator transfer unit.

The vibrator transfer unit may include a plate on which the first piezoassembly is connected to. The plate may include a first surface which isdirected towards the first assembly and a second surface which isopposite to the first surface. The first connection and the secondconnection may be applied onto the second surface of the vibratortransfer unit. Between the second surface and a surface of the housingof the vibrator available space may appear, and therefore, it would beof an advantage to arrange the first piezo assembly and/or the secondpiezo assembly within the available space as this will result in alimited size increase of the vibrator when having both the firstassembly and the first piezo assembly and/or the second piezo assembly.The plate may include a protrusion wherein the plate is configured toreceive the first and/or the at least second vibration and apply themain vibration which includes the first and/or the second vibration viathe protrusion directly onto the skull or via an implant screw fixatedto the skull of the recipient

The vibrator transfer unit may have a vibrator transfer unit center, andthe first piezo assembly and the at least second piezo assembly may bearranged symmetrically around the center of the vibrator transfer unit.By applying both piezo assemblies avoid any instability in the vibratorwhen both piezo assemblies are activated at the same.

The vibrator transfer unit may include a free-space region, wherein thefirst piezo assembly and/or the at least second piezo assembly may bearranged within the free-space region. By arranging the one or more ofthe piezo assemblies will have no or limited impact to the size of thehearing aid when applying one or more of the piezo assemblies into thevibrator. The first connection and the second connection of one or moreof the piezo assemblies may be applied to an inner surface of thevibrator transfer unit.

In another example, the vibrator transfer unit may be a rod having anupper surface which is directed towards the first assembly, and the rodmay have a side surface which the first piezo assembly and/or the secondpiezo assembly is applied to.

The first piezo assembly and/or the second piezo assembly may bearranged such that a center of the rod is overlapping the center of thefirst piezo assembly and/or the second piezo assembly. A mass may beapplied onto the first end and the second end of the first piezoassembly and/or the second piezo assembly.

In another example, the first piezo assembly and/or may be arranged in arecess of the plate of the vibrator transfer unit, and wherein an uppersurface of the plate may include the recess, and the upper surface mayalso be directed towards the first assembly configured to receive thefirst vibration provided by the first assembly.

The resonance frequency of the first and/or the second piezo assemblymay be determined by a distance between the first connection and thesecond connection or a length of the first piezo assembly and/or thesecond piezo assembly when a mass is applied to the ends of the piezoassembly. The weight of the masses does also have an impact on theresonance frequency. During a manufacturing process or a fitting processof the hearing aid to the recipient it would be of benefit to be able totune the resonance frequency specifically for the recipient for thepurpose of obtaining an optimal frequency bandwidth and powerconsumption. The distance between the resonance frequency of the firstassembly and the first piezo assembly is decisive for how improved thepower consumption will be when activating both the first assembly andthe piezo assembly.

A first position of the first connection on the first piezo assemblyand/or the second piezo assembly and a second position of the secondconnection on the first piezo assembly and/or the second piezo assemblymay be adjustable by a first adjustor and a second adjustor,respectively. The first adjustor and the second adjustor may be arrangedwithin the vibrator transfer unit and is adjustable outside the vibratortransfer unit or outside the vibrator. Each of the adjustors, i.e. thefirst adjustor and the second adjustor, may include a slider and ascrew, wherein the slider includes a first opening with threadsconfigured for receiving the screw. The screw is penetrating the slidethrough the first opening and when turning the screw the position of theslider on the screw changes. The vibrator transfer unit includes anopening or a recess for controlling each of the adjustors. The slider isconfigured to be slidable applied on the piezo assembly so that whenturning the screw the slider is configured to slide along a longitudinalaxis of the piezo assembly with friction between the slider and thepiezo assembly. The slider provides the connection of the piezo assemblyto the vibrator assembly so that the second vibration generated by thepiezo assembly is transferred to the vibrator transfer unit via thesliders. The slider may include a second opening configured to receivethe piezo assembly. Both adjustors provide the possibility of bothtuning and fine tuning the resonance frequency for obtaining an optimalperformance of the piezo assembly.

The vibrator transfer unit may include a plurality of recessesconfigured to receive at least the first piezo assembly and/or the atleast second piezo assembly, and wherein each of the recess of theplurality of recesses includes a first elevated plan and a secondelevated plan relative to a ground plane of the recess of the pluralityof recesses on which the first piezo assembly or the at least secondpiezo assembly is arranged, and the first elevation plan and the secondelevation plan provides the first connection and the second connection,respectively. The second vibration generated by the piezo assembly istransferred into the vibrator transfer unit via the elevated plans. Whenarranging a piezo assembly on both the first elevated plan and thesecond elevated plan an air gap is present between at least a part ofthe piezo assembly and at least a part of the vibrator transfer unit.The air gap is needed for the piezo assembly to vibrate in response to acurrent. The plurality of recesses may have different lengths betweenthe first and the second elevation plan providing different resonancefrequencies for the first and/or the at least second piezo assembly.Thereby, it is possible to obtain different resonance frequencies of thepiezo assembly depending on which of the plurality of recesses the piezoassembly is applied into. By applying the first and at least the secondpiezo assembly into each piezo assembly of the plurality of recesses thefrequency bandwidth of the vibrator is further improved in view of onlyhaving one piezo assembly.

The vibrator transfer unit may be divided into two parts, an upper parthaving a first surface which includes another plurality of recesses thatare similar to the plurality of recesses that is arranged in a firstsurface of the bottom part, and a second surface of the bottom part isconfigured to transfer the main vibration to the skull of the recipient.An air gap is provided between at least a part of the piezo assembly andat least a part of the first surface of both the upper part and thebottom part. The airgap on both sides of the piezo assembly is neededfor the vibrator to vibrate in response to a current. The upper part andthe bottom part may be attached by applying the first surface of theupper part against the first surface of the bottom part, and the upperpart is fixated to the bottom part by one or more screws. In view ofhaving screws and sliders for tuning the resonance frequency theplurality of recesses provides a simpler solution for tuning theresonance frequency of a piezo assembly i.e. the first piezo assemblyand/or the second piezo assembly. However, the plurality of recessesprovides limited possibility in fine tuning the resonance frequency inrelation to the solution including screws and sliders. The vibratortransfer unit may include a combined tunable solution which includesboth the screws and the sliders and the plurality of recesses havingdifferent resonance frequencies.

Combining the screws and the sliders and the plurality of recessesprovides the possibility of designing the screws and the sliders lesscomplicated as they are only used for providing the possibility of finetuning the resonance frequency of between +/−5 Hz and 50 +/−50 Hz. Inthe solution where the screws and sliders are not combined with theplurality of recesses having different resonance frequencies the tuningof the resonance frequency may be between +/−5 H<to +/−2500 Hz. Thewider tunable frequency range results in a more complex design of thescrews and the sliders.

To obtain an even simpler tunable solution which provides tunability oflarger than +/−50 Hz the plurality of recesses may be formed into onetapered recess wherein a distance between the first elevated plan andthe second elevated plan of the tapered recess has different lengthsalong a horizontal axis which is about parallel to the skull of therecipient when wearing the hearing aid. The elevated plans may betapered shaped such that the distance between the first elevated plansand the second elevated plans reduces or increases along the horizontalaxis which is also about parallel to a bottom surface of the housing ofthe vibrator.

On the second surface of the bottom part of the vibrator transfer unitincludes a protrusion configured to transfer the main vibration outsidethe housing and into the skull.

The piezo assembly, the first and/or the at least second piezo assembly,may be configured to receive a current, a first and/or a second current,in which the level is determined based on an audio signal or a firstvibration provided by the first assembly. The hearing aid may include asensor configured to monitor an output force of the second assembly andprovide a monitor signal, and a processing unit configured to determinethe level of the first current and/or the second current based on themonitor signal to obtain a wanted output force of the second assembly.The sensor may be arranged such that it is in contact with the vibratortransfer unit for detecting/monitoring the main vibration. The sensormay be the first piezo assembly, and the processing unit may beconfigured to determine the level of the first current to obtain awanted output force of the vibrator transfer unit, i.e. the secondassembly.

The first piezo assembly may be a sensor configured to monitor an outputforce of the second assembly provided by the main vibration whichincludes the first vibration, and wherein a processing unit may beconfigured to determine whether the second current should be applied tothe piezo assembly for boosting the force of the main vibration based ona monitor signal provided by the sensor. The monitor signal is based onthe monitored output force which the sensor detects via the connectionto the vibrator transfer unit. The processing unit may be configured toset the first piezo assembly into a transducer mode configured to boostthe main vibration or a sensor mode configured to monitor the outputforce of the second assembly.

The hearing aid may include a processing unit configured to control thesecond current and the first current such that the movement of the firstpiezo assembly and the movement of the first assembly interacts suchthat the first vibration and the second vibration interacts resulting inthe main vibration being transferred to the skull by the vibratortransfer unit. By activating both the first assembly and the piezoassembly results in an improved power consumption as the first assemblyhas a highly inductive behavior to the piezo assembly (the first and/orthe second piezo assembly), and the piezo assembly has a highlycapacitive behavior. That results in that the piezo assembly recoverssome of the energy generated by the first assembly, and that energy isused for generating the second current (and/or the third current) usedfor activating the first piezo assembly (and/or the second piezoassembly).

Aforementioned features shall be considered to be disclosed in anycombination with each other. Further, the disclosure of any means forperforming a method step shall be understood to also disclose therespective method step and the disclosure of a method step shall beunderstood to also disclose respective means for performing the step.

BRIEF DESCRIPTION OF DRAWINGS

The aspects of the disclosure may be best understood from the followingdetailed description taken in conjunction with the accompanying figures.The figures are schematic and simplified for clarity, and they just showdetails to improve the understanding of the claims, while other detailsare left out. Throughout, the same reference numerals are used foridentical or corresponding parts. The individual features of each aspectmay each be combined with any or all features of the other aspects.These and other aspects, features and/or technical effect will beapparent from and elucidated with reference to the illustrationsdescribed hereinafter in which:

FIGS. 1A to 1C illustrate different examples of a hearing aid;

FIGS. 2A to 2D illustrate a cross-section of different examples of avibrator;

FIGS. 3A to 3D illustrate a cross-section of different examples of avibrator;

FIGS. 4A to 4C illustrate different examples of a vibrator transferunit;

FIGS. 5A and 5B illustrate a piezo assembly;

FIGS. 6A to 6E illustrate a vibrator transfer unit; and

FIG. 7 illustrates a curve including measured force output.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations. Thedetailed description includes specific details for the purpose ofproviding a thorough understanding of various concepts. However, it willbe apparent to those skilled in the art that these concepts may bepracticed without these specific details. Several aspects of theapparatus and methods are described by various blocks, functional units,modules, components, circuits, steps, processes, algorithms, etc.(collectively referred to as “elements”). Depending upon particularapplication, design constraints or other reasons, these elements may beimplemented using electronic hardware, computer program, or anycombination thereof.

A hearing aid may be adapted to improve or augment the hearingcapability of a user by receiving an acoustic signal from a user'ssurroundings, generating a corresponding audio signal, possiblymodifying the audio signal and providing the possibly modified audiosignal as an audible signal to at least one of the user's ears.‘Improving or augmenting the hearing capability of a user’ may includecompensating for an individual user's specific hearing loss. Suchaudible signals may be provided in the form of an acoustic signalradiated into the user's outer ear, or an acoustic signal transferred asmechanical vibrations to the user's inner ears through bone structure ofthe user's head and/or through parts of the middle ear of the user orelectric signals transferred directly or indirectly to the cochlearnerve and/or to the auditory cortex of the user.

A “hearing system” refers to a system comprising one or two hearingdevices, and a “binaural hearing system” or a bimodal hearing systemrefers to a system comprising two hearing aids where the hearing aidsare adapted to cooperatively provide audible signals to both of theuser's ears either by acoustic stimulation only, acoustic and mechanicalstimulation, mechanical stimulation only, acoustic and electricalstimulation, mechanical and electrical stimulation or only electricalstimulation. The hearing system, the binaural hearing system or thebimodal hearing system may further include one or more auxiliarydevice(s) that communicates with at least one hearing aid, the auxiliarydevice affecting the operation of the hearing aids and/or benefittingfrom the functioning of the hearing aids. A wired or wirelesscommunication link between the at least one hearing aid and theauxiliary device is established that allows for exchanging information(e.g. control and status signals, possibly audio signals) between the atleast one hearing device and the auxiliary device. Such auxiliarydevices may include at least one of a remote control, a remotemicrophone, an audio gateway device, a wireless communication device,e.g. a mobile phone (such as a smartphone) or a tablet or anotherdevice, e.g. comprising a graphical interface, a public-address system,a car audio system or a music player, or a combination thereof. Theaudio gateway may be adapted to receive a multitude of audio signalssuch as from an entertainment device like a TV or a music player, atelephone apparatus like a mobile telephone or a computer, e.g. a PC.The auxiliary device may further be adapted to (e.g. allow a user to)select and/or combine an appropriate one of the received audio signals(or combination of signals) for transmission to the at least one hearingdevice. The remote control is adapted to control functionality and/oroperation of the at least one hearing device. The function of the remotecontrol may be implemented in a smartphone or other (e.g. portable)electronic device, the smartphone/electronic device possibly running anapplication (APP) that controls functionality of the at least onehearing device.

In general, a hearing aid includes i) an input unit such as a microphonefor receiving an acoustic signal from a user's surroundings andproviding a corresponding input audio signal, and/or ii) a receivingunit for electronically receiving an input audio signal. The hearing aidfurther includes a processing unit for processing the input audio signaland an output unit for providing an audible signal to the user independence on the processed audio signal.

The input unit may include multiple input microphones, e.g. forproviding direction-dependent audio signal processing. Such directionalmicrophone system is adapted to (relatively) enhance a target acousticsource among a multitude of acoustic sources in the user's environmentand/or to attenuate other sources (e.g. noise). In one aspect, thedirectional system is adapted to detect (such as adaptively detect) fromwhich direction a particular part of the microphone signal originates.This may be achieved by using conventionally known methods. The signalprocessing unit may include an amplifier that is adapted to apply afrequency dependent gain to the input audio signal. The signalprocessing unit may further be adapted to provide other relevantfunctionality such as compression, noise reduction, etc. The output unitmay include an one or more output transducers such as aloudspeaker/receiver for providing an air-borne acoustic signal to theear of the user, a mechanical stimulation applied transcutaneously orpercutaneously to the skull bone, an electrical stimulation applied toauditory nerve fibers of a cochlea of the user. In some hearing aids,the output unit may include one or more output electrodes for providingthe electrical stimulations such as in a Cochlear Implant, or the outputunit may include one or more vibrators for providing the mechanicalstimulation to the skull bone.

FIGS. 1A to 1C illustrate different examples of a hearing aid 1configured to apply a main vibration 2 onto a skull 4 of a recipient ofthe hearing aid 1. FIG. 1A illustrates an example where the hearing aidincludes a first housing 50 and a second housing 51 which are connectedby one or more wires 55. In another example the connection may bewireless. The first housing 50 includes a vibrator 10, and the secondhousing 51 includes a coil 54 configured to communicate 56 inductivelyand through the skin 6 and to an external device 57. The second housing51 includes a magnet apparatus 52 configured to attract the externaldevice 57. In this example, a processing unit 30 is arranged within theexternal device 57. The processing unit is configured to control thevibrator 10 and the communication 56 which includes power to activatethe vibrator 10. The communication 56 may include information and/orpower. The communication 56 may be bidirectional including informationand/or power. In FIG. 1B, the vibrator 10 and the processing unit 30 arearranged within the first housing 50 and are connected via one or morewires 55. In this example, the hearing aid 1 is arranged on the skin 6,and in FIG. 1C the first housing 50 is connected to the skull 4 via animplant screw 58, and in this example the vibration 2 is transferred tothe skull via the implant screw 58, and in FIG. 1B the vibration 2 istransferred to the skull 4 via the first housing 50.

FIGS. 2A to 2D illustrate a cross-section of different examples of thevibrator 10. In each of the different examples, the vibrator 10comprises a first assembly 11 which includes a magnet 12 configured toprovide a static magnetic flux and a coil 13 configured to provide adynamic magnetic flux based on a first current, and in the presentexamples the coil is arranged around at least a part of the magnet 12.Furthermore, the vibrator 10 includes a second assembly which includes avibrator transfer unit 14 and a suspension spring 16, and wherein thefirst assembly 11 is configured to move relative to the second assemblygenerating a first vibration based on the static and the dynamicmagnetic flux, and the first vibration is transferred to the vibratortransfer unit 14. The vibrator 10 includes another vibrator source. Thisanother vibrator source is a first piezo assembly 15 configured to movebased on a second current generating a second vibration. In the presentexamples, the first piezo 15 assembly is connected (17A, 17B) to thevibrator transfer unit 14, and when the first piezo assembly 15 moves asecond vibration is generated, and the second vibration is transferredto the vibrator transfer unit 14. The vibrator 10 generates the mainvibration 2 which is transferred to a skull of the recipient via thevibrator transfer unit 14, and wherein the vibration includes the firstvibration and/or the second vibration. In the present examples, thefirst piezo assembly 15 may be rectangular shaped or circular shaped.The first piezo assembly 15 may have at least a first end and a secondend relative to a center of the first piezo assembly 15, and wherein thefirst piezo assembly 15 has a first connection 17A to the vibratortransfer unit 14 arranged at the first end or between the first end andthe center and a second connection to the vibrator transfer unit 14arranged at the second end or between the second end and the center.FIG. 2A illustrates an example of the vibrator 10 where the vibratortransfer unit 14 includes a plate 14 which has a first surface directedtowards the first assembly 11 and a second surface opposite to the firstsurface. On the second surface a protrusion 19 is applied or build intothe 14, and the protrusion is configured to transfer the main vibration2 outside the vibrator 10 and eventually to the skull of the recipient.Furthermore, the first piezo assembly is connected to the second surfacehaving at least two connections, i.e. a first connection 17A and asecond connection 17B, to the second surface, and the generated secondvibration is transferred via the connections to the vibrator transferunit 10, and in the vibrator transfer unit 10 the main vibration 2 whichincludes the second vibration is transferred from the plate 14 and tothe protrusion 19 and out of the vibrator 10. In FIG. 2B, the vibratortransfer unit 14 is a rod on which the first piezo assembly 15 isconnected to via the first 17A and second 17B connection. At the firstend and the second end a first mass 18A and a second mass 18B areapplied to, respectively. In this example, when a current is applied tothe piezo assembly 15 the ends are bending creating a vibration which isthen applied to the rod 14 via the first 17A and second 17B connection.In FIG. 2C the first piezo assembly 15 is arranged within a free-spacesection 33 of the vibrator transfer unit 14. In this example, the firstpiezo assembly 15 is connected to an inner side of the free-spacesection 33 via the first 17A and the second 17B connection. It will beof an advantage to connect the first piezo assembly 15 to an inner sideof the free-space section 33 which is directed towards the protrusion 19for the purpose of improving the efficiency of the first piezo assembly15. FIG. 2D illustrates a similar example as in FIG. 2C but without theprotrusion 2C. In this example, the vibrator transfer unit 14 is a platewhich transfer the main vibration 2 to a surface of the housing 10 whichis directed towards the skull 4 when the recipient is wearing thehearing aid 1. In the examples illustrated in FIGS. 2A to 2D theconnections (17A, 17B) are arranged on a surface of the vibratortransfer unit 14 which is directed away from the first assembly 11.

FIGS. 3A to 3D illustrate a cross-section of different examples of thevibrator 10 including both the first piezo assembly 15A and a secondpiezo assembly 15B. In FIG. 3A the first piezo assembly 15A is connectedto the vibrator transfer unit 14 via the first 17A and the second 17Bconnection, and the second piezo assembly 15B is connected to thevibrator transfer unit 14 via the first 17AA and the second 17BBconnection. In this example, the connections of both piezo assemblies(15A, 15B) are overlapping, and a length of both piezo assemblies (15A,15B) are the same. In this example, the piezo assemblies (15A, 15B) areused for boosting the main vibration 2 within a specific frequency.While activating both piezo assemblies (15A, 15B) at the same timeresults in a significant increase of the force applied to the skull viathe main vibration 2. The first 17AA and the second 17BB connection ofthe second piezo assembly 15B may be connected to the vibrator transferunit 14 via the first and the second connection of the first piezoassembly 15A. In FIG. 3B, the first connection 17A and the secondconnection of the first piezo assembly 15 is arranged between the firstconnection 17AA and the second connection 17BB of the second piezoassembly. In this example, the length of the first 15A and the second15B piezo assembly is different, wherein the first piezo assembly 15A isshorter than the second piezo assembly resulting in different resonancefrequencies. The connections (17A, 17AA, 17B, 17BB) of both piezoassemblies are directly applied to the vibrator transfer unit 14. Bothpiezo assemblies extend mainly in a direction perpendicular to alongitudinal axis of the protrusion (19). The longitudinal axis ispartially perpendicular to a skull surface of the recipient of thehearing aid when the recipient wears the hearing aid. Both piezoassemblies have a longitudinal axis which is orthogonal to thelongitudinal axis of the protrusion (19). Both piezo assemblies has twoends between the longitudinal axis, and the connections (17A, 17AA, 17B,17BB) may be arranged at the ends or between the two ends of therespective piezo assembly. Between the connections (17AA, 17BB) of thesecond piezo assembly 15B the first piezo assembly 15A is arranged, andthereby, it is possible to design a vibrator having a piezo assemblywith an improved frequency bandwidth and more compact as the free spacebetween the connections (17AA,17BB) of the second piezo assembly isexplored by another piezo assembly. FIG. 3C illustrates yet anotherexample of the vibrator 10. In this example, the vibrator transfer unit14 is a plate having a thickness which is suitable for arranging a firstpiezo assembly 15A within a free space area of the plate. In thisexample the free space area is a closed free space area which issurrounded by a material of the plate. In this example, the connections(17A,17B) of the first piezo assembly 15A are arranged onto an innersurface of the vibrator transfer unit 14. A second piezo assembly isconnected (17AA, 17BB) to a surface of the vibrator transfer unit 14which is opposite to another surface facing the first assembly 11. Thesecond piezo assembly 15B is arranged between the vibrator transfer unit14 and the suspension spring 16. In FIG. 3D the vibrator transfer unit14 is an elongated shaped protrusion which may be shaped as arectangular, a conical or a cylindrical protrusion. The vibratortransfer unit 14 has a side surface on which the piezo assemblies(15A,15B) are connected (17A,17B,17AA,17BB) to. At each end of the piezoassemblies (15A,15B) a mass (18A,18AA) is applied and the masses foreach of the piezo assembly (15A,15B) have a certain weight for obtaininga certain resonance frequency. In this example, the piezo assemblies arecircular or square shaped having an opening in the center configured toreceive the vibrator transfer unit 14.

FIGS. 4A to 4C illustrate different examples of a vibrator transfer unit14. In these examples, the vibrator transfer unit 14 is circular shaped.In another example, the vibrator transfer unit 14 may be square shapedor any shape which has an optimal shape to a housing accommodating thevibrator 10. The optimal shape results in an even more compact size ofthe housing. Furthermore, the vbrator transfer unit 14 includes a firstaxis 20A and a second axis 20B intersecting at a center of the vibratortransfer unit 14. In FIG. 4A, a first piezo assembly 15A is arranged ona side of the second axis 20B which is opposite to the side on which asecond piezo assembly 15B is arranged. In this specific example, thelengths of the piezo assemblies (15A,15B) are different for the purposeof improving the frequency bandwidth of the vibrator 10. In anotherexample, the lengths may be the same for the purpose of using the secondpiezo assembly 15B for boosting the output force of the main vibration.In this example, the processing unit may be configured to turn on or offthe second piezo assembly 15B for boosting the output force based on anaudio signal provided by a microphone of the hearing aid. In anotherexample the boosting may be initiated by the processing unit if an erroris detected on the first piezo assembly. The error may result in a loweroutput force which is detected by the processing unit and a sensor. Thesensor may be the second piezo assembly 15B. In this example, theboosting results in an output force which corresponds to the outputforce of a fully functional piezo assembly 15A. FIG. 4B illustrates yetanother example of the vibrator transfer unit 14, and in this example,the unit 14 includes four piezo assemblies (15A-15D) all havingdifferent lengths. In this example, the piezo assemblies (15A-15D) arearranged asymmetric around the second axis 20B but symmetrical aroundthe first axis 20A. In FIG. 4C, the four piezo assemblies are arrangedsymmetrically around both the first and the second axis (20A, 20B). Thisexample provides a more harmonic vibration onto the vibrator transferunit 14.

FIGS. 5A and 5B illustrate a piezo assembly 15, and FIG. 5A illustratesa piezo assembly 15 having a single layer 75 comprising a conductivematerial, and FIG. 5B illustrates a piezo assembly 15 having multiplelayers (75A-75C) of same conductive material or different conductivematerials. Each of the layers (75,75A-75C) has a first end 70 and asecond end 71 relative to a center 73 of the piezo assembly 15.

FIGS. 6A to 6E illustrate a vibrator transfer unit 14 including meansfor adjusting the position of the connections (17A,17B,17AA,17BB) thatresults in a change of the resonance frequency of each piezo assembly.This may also affect the frequency bandwidth of the vibrator 10. Thepossibility of having means for adjusting the resonance frequency isneeded if wanting to either tuning or fine tuning the resonancefrequency or the frequency bandwidth of the vibrator 10 specifically forthe recipient of the hearing aid. FIG. 6A illustrates an example whichincludes a first adjustor 31A and a second adjustor 31B both arrangedwithin the vibrator transfer unit 14 but accessible outside the vibratortransfer unit 14. In this example, both adjustors (31A, 31B) are a screwwhich is connected to a connector (17A,17B) which is configured to slidein a direction parallel to an axis 20 while turning the screw. Thereby,it is possible to adjust the distance between the connections (17A, 17B)while turning the screws (31A,31B). In this example, the vibratortransfer unit 14 may optionally have a protrusion 19. In FIG. 6B, thevibrator transfer unit 14 is square shaped which makes it possible toapply more piezo assemblies (15) with certain lengths than if thevibrator transfer unit 14 was circular shaped. In this example, thevibrator transfer unit includes multiple recesses 32 where each of therecess includes a first connection (17A,17AA,17D,17DD) and a secondconnection (17B,17BB,17C,17CC), and where the first connection and theconnection is an elevated plane in relative to a ground plane formedbetween the first and second connection. When arranging a piezo assembly15 onto the elevated planes (17A,17AA,17D,17DD, 17B,17BB,17C,17CC), afree space is obtained between the piezo assembly 15 and the groundplane. The free space allows the piezo assembly 15 to vibrate. In theexample illustrated in FIG. 6B, the length of the ground plane isdifferent. The vibrator transfer unit 14 provides the possibility foradjusting the resonance frequency and/or the frequency bandwidth of thevibrator. It is obvious that similar effect will appear if arranging aplurality of piezo assemblies into two or more of the recesses. FIG. 6Cillustrates an example where the plurality of recesses is formed intoone tapered recesses 32. The vibrator transfer unit 14 includes a firstconnection 17A and a second connection 17B having a distance between thefirst and the second connection (17A,17B) which varies along the firstaxis 20A. The variation in distance is tapered shaped meaning that thedistance gradually changes along the first axis 20A. The firstconnection and the second connection (17A,17B) are elevated planes inrelative to a ground plane arranged between the first and the secondconnection (17A,17B). The plurality of recesses 32 is formed into onetapered recess wherein a distance between the first elevated plan 17Aand the second elevated plan 17B of the tapered recess 32 has differentlengths along a horizontal axis 20A which is about parallel to the skullof the recipient when wearing the hearing aid. FIGS. 6D and 6Eillustrate that the vibrator transfer unit 14 comprises a first part 14Aand a second part 14B which are mirrored in such a way that both parts(14A, 14B) include the plurality of recesses 32. In FIG. 6E, one of theparts (14A,14B) includes optionally the protrusion 19.

FIG. 7 illustrates a curve including measured force output (43,42,41)versus frequency for the vibrator 10. The full line 43 illustrates theoutput force of the first assembly 11, the dotted line 42 is the outputforce of the first piezo assembly 15A, and the space-dotted line 41 isthe output force of the second piezo assembly 15B. The curve 44illustrates the main vibration created by the vibrations provided by thethree assemblies (11, 15A, 15B).

In all of the figures mentioned above, the hearing aid may include asensor configured to monitor an output force of the first piezoassembly, i.e. the second assembly (15), and provide a monitor signal,and the processing unit 30 is configured to determine the level of thefirst current and/or the second current based on the monitor signal toobtain a wanted output force of the second assembly 15. The sensor isthe first piezo assembly 15, and the processing unit is configured todetermine the level of the first current to obtain a wanted output forceof the second assembly. In another example, the second piezo assembly15B may be the sensor.

As used, the singular forms “a,” “an,” and “the” are intended to includethe plural forms as well (i.e. to have the meaning “at least one”),unless expressly stated otherwise. It will be further understood thatthe terms “includes,” “comprises,” “including,” and/or “comprising,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. It will also be understood that when an element is referred toas being “connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element, but an intervening elementmay also be present, unless expressly stated otherwise. Furthermore,“connected” or “coupled” as used herein may include wirelessly connectedor coupled. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. The steps ofany disclosed method are not limited to the exact order stated herein,unless expressly stated otherwise.

It should be appreciated that reference throughout this specification to“one embodiment” or “an embodiment” or “an aspect” or features includedas “may” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the disclosure. Furthermore, the particular features,structures or characteristics may be combined as suitable in one or moreembodiments of the disclosure.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Reference to an element in the singular is not intendedto mean “one and only one” unless specifically so stated, but rather“one or more.” Unless specifically stated otherwise, the term “some”refers to one or more.

Accordingly, the scope should be judged in terms of the claims thatfollow.

1. A hearing aid configured to apply a main vibration onto a skull of arecipient of the hearing aid, and wherein the hearing aid includes avibrator comprising: a first assembly which comprises a magnetconfigured to provide a static magnetic flux and a coil configured toprovide a dynamic magnetic flux based on a first current, and the coilis wrapped around at least a part of the magnet, a second assembly whichincludes a vibrator transfer unit and a suspension spring, and whereinthe first assembly is configured to move relative to the second assemblygenerating a first vibration based on the static and the dynamicmagnetic flux, and the first vibration is transferred to the vibratortransfer unit, a first piezo assembly configured to move based on asecond current generating a second vibration, and wherein the firstpiezo assembly is connected to the vibrator transfer unit, and when thefirst piezo assembly moves a second vibration is generated, and thesecond vibration is transferred to the vibrator transfer unit, andwherein the main vibration is transferred to a skull of the recipientvia the vibrator transfer unit, and wherein the vibration includes thefirst vibration and/or the second vibration.
 2. A hearing aid accordingto claim 1, comprising a processing unit configured to determine thefirst current and the second current based on an audio signal providedby at least one microphone of the hearing aid.
 3. A hearing aidaccording to claim 1, wherein the vibrator includes at least a secondpiezo assembly configured to move based on a third current and generatea third vibration, and wherein the at least second piezo assemblytransfer the third vibration to the vibrator transfer unit, and whereinthe main vibration to the skull includes at least the first vibrationand/or the second vibration and/or the third vibration.
 4. A hearing aidaccording to claim 1, wherein the first piezo assembly has at least afirst end and a second end relative to a center of the first piezoassembly, and wherein the first piezo assembly has a first connection tothe vibrator transfer unit arranged at the first end or between thefirst end and the center and a second connection to the vibratortransfer unit arranged at the second end or between the second end andthe center.
 5. A hearing aid according to claim 3, wherein the at leastsecond piezo assembly has at least a first end and a second end relativeto a center of the at least second piezo assembly, and wherein the atleast second piezo assembly has a first connection to the vibratortransfer unit arranged at the first end or between the first end and thecenter of the at least second piezo assembly and a second connection tothe vibrator transfer unit arranged at the second end or between thesecond end and the center of the at least second piezo assembly.
 6. Ahearing aid according to claim 4, wherein the vibrator transfer unitincludes a vibrator transfer unit center, and the first piezo assemblyand the at least second piezo assembly are arranged symmetrically aroundthe center of the vibrator transfer unit.
 7. A hearing aid according toclaim 1, comprising a processing unit configured to control the firstcurrent and the second current such that the movement of the first piezoassembly and the movement of the first assembly interacts such that thefirst vibration and the second vibration interacts resulting in the mainvibration being transferred to the skull by the vibrator transfer unit.8. A hearing aid according to claim 3, wherein the first piezo assemblyand/or the at least second piezo assembly is connected to an outersurface of the vibrator transfer unit.
 9. A hearing aid according toclaim 3, wherein a free-space region is arranged within the vibratortransfer unit, and wherein the first piezo assembly and/or the at leastsecond piezo assembly is arranged within the free-space region.
 10. Ahearing aid according to claim 4, wherein a first position of the firstconnection on the first piezo assembly and/or the second piezo assemblyand a second position of the second connection on the first piezoassembly and/or the second piezo assembly, are adjustable by a firstadjustor and a second adjustor, respectively.
 11. A hearing aidaccording to claim 10, wherein each of the first adjustor and the secondadjustor is arranged within the vibrator transfer unit and is adjustableoutside the vibrator transfer unit or outside the vibrator.
 12. Ahearing aid according to claim 4, wherein the vibrator transfer unitincludes a plurality of recesses configured to receive at least thefirst piezo assembly and/or the at least second piezo assembly, andwherein each of the recess of the plurality of recesses includes a firstelevated plan and a second elevated plan in relative to a ground planeof the recess of the plurality of recesses on which the first piezoassembly or the at least second piezo assembly is arranged, and thefirst elevation plan and the second elevation plan provides the firstconnection and the second connection, respectively.
 13. A hearing aidaccording to claim 12, wherein the plurality of recesses has differentlengths between the first and the second elevation plan providingdifferent resonance frequencies for the first and/or the at least secondpiezo assembly.
 14. A hearing aid according to claim 12, wherein thevibrator transfer unit is divided into two parts, an upper part having afirst surface which includes another plurality of recesses that aresimilar to the plurality of recesses that is arranged in a first surfaceof the bottom part, and a second surface of the bottom part isconfigured to transfer the main vibration to the skull of the recipient.15. A hearing aid according to claim 14, wherein the upper part and thebottom part are attached by applying the first surface of the upper partagainst the first surface of the bottom part, and the upper part isfixated to the bottom part by one or more screws.
 16. A hearing aidaccording to claim 12, wherein the plurality of recesses is formed intoone tapered recess wherein a distance between the first elevated planand the second elevated plan of the tapered recess has different lengthsalong a horizontal axis configured to be about parallel to the skull ofthe recipient when wearing the hearing aid.
 17. A hearing aid accordingto claim 1, comprising a sensor configured to monitor an output force ofthe second assembly and provide a monitor signal, and a processing unitconfigured to determine the level of the first current and/or the secondcurrent based on the monitor signal to obtain a wanted output force ofthe second assembly.
 18. A hearing aid according to claim 17, whereinthe sensor is the first piezo assembly, and the processing unit isconfigured to determine the level of the first current to obtain awanted output force of the second assembly.
 19. A hearing aid accordingto claim 1, wherein the first piezo assembly is a sensor configured tomonitor an output force of the second assembly provided by the mainvibration which includes the first vibration, and wherein a processingunit is configured to determine whether the second current should beapplied to the piezo assembly for boosting the main vibration based on amonitor signal provided by the sensor.
 20. A hearing aid according toclaim 19, wherein the processing unit is configured to set the firstpiezo assembly into a transducer mode configured to boost the mainvibration or a sensor mode configured to monitor the output force of thesecond assembly.